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Current time:0:00Total duration:3:29

Recognizing common 3D shapes

Video transcript

so I have five three-dimensional shapes over here and I also have five names for them and what I want you to do is pause this video and think about which of these shapes is a square pyramid which of these is a rectangular prism which one is a triangular prism which one is a sphere and which one is a cylinder all right now let's just work through this together and really this is just something to know because some people in various subjects will sometimes throw out these words so first let's start let's think about which one is the square pyramid so this shape here on the right clearly looks like a pyramid and the thing that makes it a square pyramid is the idea that its base is a square let me see if I can shade this in so the base of this right over here is is a square and so that's where the square pyramid comes from if it's a triangular pyramid then the base would only have three sides but this is a square pyramid so let me move this over there so that is a square pyramid all right let's do the next one which one is a rectangular prism a prism you can view is a three-dimensional object and since it's since it's saying a rectangular prism well the best one here that is rectangular notice this shape right over here is rectangular on every side and it's three dimensions it is a prism and so this is the rectangular prism so let's move that over so that is our rectangular prism now triangular prism so this one is interesting if you look at this shape right over here it has sides that are triangles you see this up here is a triangle and you see this down here is a triangle although they're connected by these rectangular sides and this is actually what's called a triangular prism in a square pyramid the faces which are triangles all meet at a point in a triangular prism you have two opposite facing sides that our triangles and you'll see all of these in different orientations in different you know sometimes it'll be resting like this sometimes it'll be on its side but this is a triangular prism let me see that is a triangular prism and so we have two left you might be able to figure these out which one is a sphere well when I think sphere I think of like a globe and so this choice right over here is clearly a sphere so let me move that over let me move it over okay so that one is a sphere and then last but not least a thing that looks like a can is a cylinder so let me move that over so that is a cylinder and we're all done and so these are just useful names to know for shapes cylinder is your connecting you have these two faces that are circular and then they are opposite each other it's kind of like a triangular prism but instead of having these hard edges because you have a triangle you have a base that is a circle and a top that is a circle